Vehicles are designed to travel through a body of water up to a finite depth, which may be referred to as a maximum wading depth. Beyond this maximum wading depth there is a risk that the vehicle engine and electronics may be damaged. Vehicles with off-road capability are designed to have the ability to wade through water at greater depth than conventional vehicles; however the maximum wading depth may differ from vehicle to vehicle. The maximum wading depth may also be dependent to some extent upon the skill of the driver. Prior to wading it is recommended to make an assessment of water depth and underwater terrain on foot. Impatience may result in an attempted traverse by vehicle without taking adequate precautions.
An on-board measurement of the depth of the water whilst wading may be an asset to the driver. An estimation or measurement of water depth some distance in front of the vehicle may also be an advantage, giving the driver advance indication of future immersion depth and information about an immersion limit.
Absolute measurement of water depth some distance in front of the vehicle by remote means is difficult and expensive. However an estimation of water depth may still provide a useful indication to the driver that caution may be necessary.